Design and analysis of a soft mobile robot composed of multiple thermally activated joints driven by a single actuator

Cheng, Nadia; Ishigami, Genya; Hawthorne, S.; Chen, Hao; Hansen, Michael K.; Telleria, Maria; Playter, Robert; Iagnemma, Karl

doi:10.1109/robot.2010.5509247

Cited by 70 publications

(41 citation statements)

References 9 publications

(12 reference statements)

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“…Specifically, we present the design and analysis of a robotic manipulator composed of 1) serial modules that can transition between rigid and flexible states via jamming and 2) tension cables running along the length of the manipulator and whose lengths are controlled by spooler motors. We previously demonstrated this robotic architecture of coupling locally tunable stiffness with global actuation as a thrust toward soft robotics [8] [9]. One of the main benefits of this type of system is that by eliminating the need for distributed-and often rigid and bulky-actuators throughout the robot, the system can be more robust and flexible, enabling it to conform to its environment better.…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of a Robust, Low-cost, Highly Articulated manipulator enabled by jamming of granular media

Cheng

Lobovsky

Keating

et al. 2012

2012 IEEE International Conference on Robotics and Automation

257

163

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Abstract-Hyper-redundant manipulators can be fragile, expensive, and limited in their flexibility due to the distributed and bulky actuators that are typically used to achieve the precision and degrees of freedom (DOFs) required. Here, a manipulator is proposed that is robust, high-force, low-cost, and highly articulated without employing traditional actuators mounted at the manipulator joints. Rather, local tunable stiffness is coupled with off-board spooler motors and tension cables to achieve complex manipulator configurations. Tunable stiffness is achieved by reversible jamming of granular media, which-by applying a vacuum to enclosed grainscauses the grains to transition between solid-like states and liquid-like ones. Experimental studies were conducted to identify grains with high strength-to-weight performance. A prototype of the manipulator is presented with performance analysis, with emphasis on speed, strength, and articulation. This novel design for a manipulator-and use of jamming for robotic applications in general-could greatly benefit applications such as human-safe robotics and systems in which robots need to exhibit high flexibility to conform to their environments. [6], and to create a variable stiffness endoscopic tube [7]. The combination of these projects highlights the primary benefits of utilizing jamming for robotics:it allows robots to be more human-safe, inexpensive, and robust compared to most technologies that have traditionally been used for such applications.The goal of this paper is to further the use and understanding of jamming for engineering applications. Specifically, we present the design and analysis of a robotic manipulator composed of 1) serial modules that can transition between rigid and flexible states via jamming and 2) tension cables running along the length of the manipulator and whose lengths are controlled by spooler motors. We previously demonstrated this robotic architecture of coupling locally tunable stiffness with global actuation as a thrust toward soft robotics [8] [9]. One of the main benefits of this type of system is that by eliminating the need for distributed-and often rigid and bulky-actuators throughout the robot, the system can be more robust and flexible, enabling it to conform to its environment better. In addition, the cost of the robot can be drastically reduced.In this paper we also begin to explore how grain properties affect the performance of jammed systems. Specifically, we seek to maximize the strength-to-weight ratio of jammed systems. This is an important figure of merit for manipulators, where the robot must be able to support its own weight in addition to any payloads.Because granular systems inherently lack mechanical structure in their unjammed states, their flexibility and high DOFs can be beneficial for hyper-redundant robotic systems such as a manipulator. Most approaches in hyper-redundant robotics have involved employing distributed and rigid pneumatic or electromagnetic actuators. Much of the effort in this area has been in dev...

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Section: Introductionmentioning

confidence: 99%

Design and Analysis of a Robust, Low-cost, Highly Articulated manipulator enabled by jamming of granular media

Cheng

Lobovsky

Keating

et al. 2012

2012 IEEE International Conference on Robotics and Automation

257

163

View full text Add to dashboard Cite

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“…• Solder: A worm-like robot demonstrates the use of polymeric elements connected by solder-joints for controllable stiffness performances [44]. A crawling robot with "solder-activated joints" uses joints with the phase-change as the locking mechanism [45].…”

Section: Methodsmentioning

confidence: 99%

“…The global stiffness of the device can be adjusted by controlling the temperature of each element and joint. The elements contain thermorheological fluids, while the joints are made of solder-alloy mixture (60Sn-40Pb and Chip Quik) to lock or unlock the structure [44].…”

Section: Methodsmentioning

confidence: 99%

Flexible Medical Devices: Review of Controllable Stiffness Solutions

2017

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Abstract:In the medical field and in soft robotics, flexible devices are required for safe human interaction, while rigid structures are required to withstand the force application and accuracy in motion. This paper aims at presenting controllable stiffness mechanisms described in the literature for applications with or without shape-locking performances. A classification of the solutions based on their working principle is proposed. The intrinsic properties of these adaptive structures can be modified to change their mechanical characteristics from a geometrical point of view or equivalent elastic properties (with internal mechanisms or with a change in material properties). These solutions are compared quantitatively, based on selected criteria linked to the medical field as the stiffness range, the activation time and the working conditions. Depending on the application and its requirements, the most suitable solution can be selected following the quantitative comparisons. Several applications of these tunable stiffness structures are proposed and illustrated by examples of the literature.

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“…However, there are limitations in their achievable range of the elastic modulus, or yield strength, when they are activated. Thermally activated materials such as wax or solder can also be used as tunable-stiffness elements to create locking mechanisms in soft robotic applications [17,18]. However, achieving tunable stiffness with these materials requires long activation times (typically on the order of seconds).…”

Section: A Stiffness-adjustable Hyper-redundant Manipulator Using a Vmentioning

confidence: 99%

A Stiffness-Adjustable Hyperredundant Manipulator Using a Variable Neutral-Line Mechanism for Minimally Invasive Surgery

Cheng²,

et al. 2014

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Abstract-In robotic single port surgery, it is desirable for a manipulator to exhibit the property of variable stiffness. Small port incisions may require both high flexibility of the manipulator for safety purposes, and high structural stiffness for operational precision and high payload capability. This paper presents a new hyper-redundant tubular manipulator with a variable neutral-line mechanisms and adjustable stiffness.A unique asymmetric arrangement of the tendons and the links realizes both articulation of the manipulator and continuous stiffness modulation. This asymmetric motion of the manipulator is compensated by a novel actuation mechanism without affecting its structural stiffness.The paper describes the basic mechanics of the variable neutral-line manipulator, and its stiffness characteristics. Simulation and experimental results verify the performance of the proposed mechanism.Index Terms -Variable neutral-line mechanism, snake-like manipulator, adjustable stiffness, medical robot.

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Design and analysis of a soft mobile robot composed of multiple thermally activated joints driven by a single actuator

Cited by 70 publications

References 9 publications

Design and Analysis of a Robust, Low-cost, Highly Articulated manipulator enabled by jamming of granular media

Design and Analysis of a Robust, Low-cost, Highly Articulated manipulator enabled by jamming of granular media

Flexible Medical Devices: Review of Controllable Stiffness Solutions

A Stiffness-Adjustable Hyperredundant Manipulator Using a Variable Neutral-Line Mechanism for Minimally Invasive Surgery

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